Dry pipe exhauster



June 7, 1932. BENSON 1,861,777

DRY PIPE EXHAUSTER Filed April 15,1931 Z SheetS-Sheet 2.

Patented June 7, 1932 1,861,777

in UNlTED srarns PATENT OFFICE DRY PIPE EXHAUSTER Application filed April 13, 1931. Serial No. 529,598.

This invention relates to sprinkler systems erated from each other by suitable partition in which the distributing pipes are normally members 23 and 24. filled with air under pressure, which air must A pipe 25 (F ig. 1) connects the compart- I be released before water can enter to supply ment 20 tthe dry pipe sprinkler system an open sprinkler head. above the usual dry pipe valve. The air 55' If all of the air in the sprinkler system is chamber is a pressure chamber, the chamforced out through the relatively small openber 21 a relay chamber and the chamber22 ings at one or two' open sprinkler heads, a an exhaust chamber. A vent pipe 27 conconsiderableperiod of time'is required before nects the compartment or chamber 22 to the i9 water can reach the open sprinklers. In oratmosphere, and a pipe 28 (Fig. 3) connects o0 derto reduce this delay, exhaust-devices have the compartment or chamber 21 to the inbeen provided, operable upon a predetertermediate chamber of the usual dry pipe mined drop in air pressure in the sprinkler valve (not shown), this chamber 21 being .system and venting the system rapidly when filled with air at atmospheric pressure under 15 suchv a: drop in pressure occurs. normal conditions. It is the object of my invention to provide An additional compartment orchambe'r 30 an improved construction of dry pipe exis formed in theintermedia-te' casing member ha-usterinwhich a relay valve is utilized to 12 and a. relatively large airstorage chamope'nazmai-n exhaust valve. A further object" ber' 32 is formed in the top or cap 13. A w of the invention is to provide a construction suitable pressure gauge 38 may be connected 7 bywhich the size of the dry pipe exhauster through a pipe 34 to the storage chamber 32 and the-d imensions of the various parts there to indicate the pressure therein, which is norof may be substantially reduced without remally equal to the air pressure in the dry timing the exhausting capacity of the device pipe system. as awhole. An opening'36 is formed in a partition 37 My: inventionfurther relates to arrangewhich separates the chambers 30 and 32 and ments and combinationsof parts which will a diaphragm' 40 is clamped against the upbe hereinafter described and 'more particuper edge" of" the intermediate casing member larly pointed out in the appended claims. 12 and underlies the opening 36. A preferred form ofthe invention is shown A. restricted bleed opening 42 is formed in in the drawings in which a cross partition of a; bushing 43, extending Fig. 1 is asectional side elevation of my through the middle portion or" the-diaphragm improved d'ry plpe exhauster; 40' and secured thereto by a flanged clam ing Fig; 2 is a plan view of the eXh-auster, par nut 44. Screens 46 aresecured above an bely' in section; I low the bleed opening 42 bycapsor bushings' Fig. 3-2111; end elevation thereof, partly in 17 having air passages 48 formed therein. section; and lVith this construction, it will be evident Fig; lis a view similar to Fig. 1 but showthat air canv pass slowly back and forth being the pants in a different position. tween the chambers 30 and '32, tending to- R f i t thedrawings,myimproveddry equalize the pressures therein. pipe exhauster comprises a as ng C pref- A. large exhaust port 50 is formed in the erably formedof a body 10, a bottom mempartitionmember 23' which separates the casber 11, and intermediate. section 12, and a in chambers 20 a=nd 22. An exhaust valve wpmember ,31 The bottom member 52 is mounted below the opening 50 andis llis securedto thebody 10 by suitable clamppushed upward against a seating ring 53 by ing screws loand the top 13 and intermediate a coil spring 54. member 12 are secured to the body 10 by ad- The valve 52 is preferably provided with ditionall clamping; screws 17 (Fig. 2' and 3). a disc 56 of leather or other suitable ack- The body 10 is formed with three compartin mate'rial', which engages the seatingring ments or air chambers 20, 21, and 22, Sep- '53 around its periphery and also engages the' 109 lower end of a sleeve or bushing 58, threaded into an opening 59 in the partition member 24 which separates the chambers 21 and 22. The bushing 58 not only provides an inner annular seat for the valve but also constitutes a guide for the valve stem 60 extending upwardly from the valve 52.

A diaphragm 62 is clamped between the casing parts 10 and 12 and forms the upper wall of the chamber 21. A disc 68 is secured in the center of the under side of the dia phragm 62, in position to engage the valve stem 60 when the diaphragm 62 is depressed. A small bushing 65 is mounted in the diaphragm 62, with a restricted bleed opening 66 extending therethrough.

A bushing 70 is secured in an opening in the partition 71 which forms the bottom of the air chamber 00. The upper end of the bushing 70 forms a seat for a relay valve 72 having a loosely fitting valve stem 7 3 extending downward through the opening in the bushing.

The valve 72 is engaged by a valve lever 75, mounted on a fixed pivot 76 and having an end portion 77 positioned for engagement by the lower end of the cap or bushing 47 carried by the diaphragm 40. A spring 78 holds the valve 7 2 normally seated.

Having described the construction of my improved dry pipe exhauster, the use and operation thereof is as follows:

When the sprinklersystem is filled with air under pressure, the air will flow through the pipe 25 to the pressure chamber 20, raising the pressure therein and applying the increased pressure to the underside of the exhaust valve 52 to more firmly seat the valve against the seating ring 53 and the end of the bushing 58. The exhaust chamber 22 is at all times at atmospheric pressure.

Air from the pressure chamber 20 also flows freely through a connecting passage 80 to the intermediate air chamber 30, raising the pressure therein and also gradually raising the pressure in the storage chamber 32 by seepage of air through the bleed opening 42. After a suflicient interval, the air chambers 20, 30, and 32 will all contain air at substantially the same pressure as that maintained in the dry pipe system.

At this time, the relay chamber 21 is connected to the atmosphere through the pipe 28, which extends to the intermediate chamber of the dry pipe valve. Furthermore, the air in the relay space 82 above the diaphragm 62 will also be at atmospheric pressure, by reason of the bleed opening 66 through the diaphragm 62.

The valve 72 is maintained in closed position by its own weight, also by the force of the spring 78, and furthermore by the excess in pressure in the intermediate chamber 80 above the atmospheric pressure in the space 82.

Assuming now that one or more sprinkler heads open, the air pressure in the sprinkler system will being to fall, with a corresponding drop in pressure in the air pressure chamber 20, and in the intermediate chamber 30 freely connected therewith.

A higher pressure is maintained, however, in the storage air chamber 32 for a considerable period, due to the very slow rate at which air can escape from the chamber 32 through the bleed opening 42. Consequently there is an excess in pressure above the diaphragm 40, which is thereby depressed, raising the valve 72 and allowing air from the chamber 30 to fiow into the relay space 82 above the diaphragm 62.

While the pressure in the intermediate chamber 30 has been somewhat reduced by the opening of the sprinkler heads, it is still very substantially above the atmospheric pressure of the chamber 21, and consequently when the valve 72 is opened, the diaphragm 62 is pushed downward with suificient pressure to depress the exhaust valve 52 and open the large exhaust passage 50 between the pres sure chamber 20 and the exhaust chamber 22.

Thereupon, air will rush quickly through the opening 50 to the exhaust, very rapidly reducing the air pressure in the sprinkler system and allowing the air to escape therefrom, so that water may enter and be distributed to the open sprinklers.

As soon as the dry pipe valve opens and water is admitted to the sprinkler system, water is conveyed to the lower part of the relay chamber 21 through the pipe 28, thus producing a pressure equal or in excess of the pressure in the space 82.

As soon as these pressures are equalized, the spring 54 moves the exhaust valve 52 upward, closing the exhaust opening 50 and pre venting escape of water through the exhaust pipe 27. The seating of the packing member 56 against the ring 58 forms a tight joint and prevents the escape of water from the pressure chamber 20, and the seating of the packing disc against the lower end of the bushing 58 forms a second tight joint which prevents escape of water from'the relay chamber 21. Consequently all objectionable leakage or dripping from the exhaust pipe 27 is avoided.

Having described the operation of my improved exhauster, it will be evident that the use of the relay valve 72 permits a substantial reduction in the diameter of the diaphragm 62. t

In exhausters previously used, the large exhaust valve 52 was operated directly by the upper diaphragm 40, so thatthe force available for opening the exhaust valve was merely the difference in pressure kler system and the air storage chamber 32. This difference being relatively small, the, diaphragm 40 was necessarily of large diambetween the sprineter in order to develop enough force to overcome the pressure on the exhaust valve 52.

In my improved construction, however, the force available for opening the exhaust valve 52 is the diiferencebetween the slightly re duced pressure in the intermediate chamber.

and atmospheric. This difference in pressure is many times greater than the difference in pressure previously available, and consequently the diameter of the diaphragm 62 may be proportionately reduced, with a corresponding reduction in the size of the casing C and in the size of many of the associated parts.

The necessary difference in pressure between the air storage chamber 32 and the intermediate chamber 30 to open the relay valve 72 is comparatively small and may be adjusted by varying the tension of the spring 78. The spring is usually adjusted so that a diiference of two or three pounds in pressure between the air chambers 32 and 30 will cause the relay valve 72 to be opened. The sensitiveness of the device may also be increased by decreasing the size of the port opening for the relay valve 7 2, or by changing the ratio of the arms of the valve lever It should be noted thatthe relay valve 72 is normally closed not only by the pressure of the spring 78 but also by its own weight and by the substantial pressure of the air in the chamber 30.

Having described the details of construction of my improved air exhauster, it will be seen that the device is simple and reliable, containing few moving parts, and that substantial pressure is available for opening the exhaust valve 52 on a relatively small but rapid drop in sprinkler system pressure.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is 1. An air exhauster comprising a pressure chamber continuously open to the sprinkler system, a vented exhaust chamber, a partition separating said chambers and having a relatively large exhaust port opening therethrough, an exhaust valve normally closing said opening, a spring assisting to close said exhaust valve, a relay chamber having a dia phragm mounted therein which separates said chamber into two parts continuously connected through a bleed opening, both parts of said relay chamber being normally at atmospheric pressure, a connection from said diaphragm to said exhaust valve, an intermediate air chamber in free communication with said pressure chamber, a normally closed relay valve between said intermediate chamber and one part of said relay chamber and opening toward said intermediate chamber, and means to open said relay valve upon a set forth in claim 1, in which said latter means comprises an air storage chamber separated from said intermediatechamber by a diaphragm and continuously connected thereto through a second bleed opening, a lever connected to said relay valve, and a device on said diaphragm engaging said lever and effective to open said valve when said diaphragm is displaced toward said intermediate cham- 4. The combination in an air exhauster as set forth in claim 1, in which said latter means comprises an air storage chamber separated from said intermediate chamber by a diaphragm and continuously connect-ed thereto through a second bleed opening, and a spring for supplementing the excess of air pressure above atmospheric in said intermediate chamber in holding said relay valve closed.

5. The combination in an air exhauster as set forth in claim 1, in which said latter means comprises an air storage chamber separated from said intermediate chamber by a diaphragm and continuously connected thereto through a second bleed opening, and a spring for supplementing the excess of air pressure above atmospheric in said intermediate chamber in holding said relay valve closed, said spring being adjustable to vary the pressure differential between said storage chamber and said intermediate chamber required for opening said relay valve.

6. The combination in an air exhauster as set forth in claim 1, in which said latter means comprises an air storage chamber separated from said intermediate chamber by a diaphragm and continuously connected thereto through a second bleed opening, and said bleed opening being formed in the central disc of a bushing mounted in an opening in said latter diaphragm.

7 The combination in an air exhauster as set forth in claim 1, in which the pressure chamber has an inlet opening and the exhaust chamber has an outlet opening, and in which said two openings are substantially in horizontal and axial alignment.

8. An air exhauster comprising a pressure chamber continuously open to the sprinkler system, a vented exhaust chamber, a partition separating said chambers and having a relatively large exhaust port opening therethrough, an exhaust valve normally closing said opening, a spring assisting to close said exhaust valve, a relay chamber having a diaair pressure in,

exhaust-er as phragm mounted therein which separates said chamber into two parts continuously connected through a bleed opening, both parts of said relay chamber being normally at atmospheric pressure, a valve rod for said exhaust valve extending into said relay chamber, means to introduce air under pressure to one part of said relay chamber and thereby cause said diaphragm to act through said valve rod to open said exhaust valve, and a bushing for said valve rod, said partition and said bushing having annular seats each directly engaged by said exhaust valve. In testimony whereof I have hereunto af- 15 fixed'my signature.

EMIL M. BENSON. 

